Electron discharge device



Jan. 7, 1947.

J. w. WEST ELECTRON DISCHARGE DEVICE F'iied Nov. 17, 1942 FIG. 4,, L,

lNl NTOR .1 w WEST BY Mail vb 7M ATTORNEY Patented Jan. 7, 1947 rELECTRON DISCHARGE DEVICE John W. West, Jackson Heights, N. Y., assignorto Bell Telephone Laboratories, Incorporated, New York, N. Y., acorporation of New York Application November 17, 1942, Serial No.465,839

Claims. 1

This invention relates to electron discharge devices and moreparticularly to high power devices having electrode units of extensivearea.

As electrode surfaces increase in area in discharge devices to producegreater power output the problem of supporting the electrode assembly inan evacuated enclosing vessel to resist transverse shock, which woulddistort the electrodes or cause breakage of the fragile filamentarycathode or the enclosing vessel, also increases. Heretofore it has beenthe usual practice to maintain rigidity in the electrode assembly unitor mount by providing a reinforced truss-like substructure affixed. tothe supporting stem of the vessel by a metallic collar surrounding thestem. This expedient has increased the cost and manufacturing processeswithout materially safeguarding the unit in the vessel, particularly theend of the unit furthest from the stem which is subjected to thegreatest stress and strain when lateral impact forces imperil thedevice.

The primary object of this invention is to reinforce the electrode unitin the device to withstand severe shock and vibrations.

Another object of the invention is to fabricate the assembly with aminimum of extraneous superstructure thereby decreasing the cost ofproduction and assembly.

A further object of the invention is to increase the efficiency ofoperation by the omission of large metallic masses in the vicinity ofthe stem which increase tension strain in the glass supportingconductors for the electrode supplying various potentials thereto.

These and other objects and advantages are attained in accordance withthis invention by supporting a multielectrode unit assembly from a stemof an enclosing vessel by a pair of rigid conductors sealed in the stemfor conveying current to the incandescent filamentary cathode of theelectrode mount. These conductors are rigidly secured to the mount andare reinforced by transverse braces having the ends locked in thespacing insulator support of the electrodes and the mid-portionsfastened to the conductors intermediate the unit and the stem. Thisarrangement eliminates costly stem construction and the large mass ofmetallic supporting structure adjacent the stem. Furthermore, itmaterially reduces the manufacturing processes of fabrication and lowersthe cost of assembly.

The opposite end of the electrode mount is rigidly anchored to the topof the enclosing vessel by a U-shaped yoke member which is secured tothe top insulating spacer block and having its mid-portion fastened to aconductor sealed through the top of the vessel to supply a highoperating voltage to the anode or output electrode of the device. Theyoke member is reinforced by a central rib or partition plate member tooffset angular stress in the yoke member and to impart substantialrigidity to the yoke member to any transverse shocks or otherdetrimental forces which would alter or damage the electrode elements ofthe unit or impair the uniform space relation between them.

A feature of this construction is the provision of a yieldable couplingin the yoke member to prevent endangering the hermetic sealed joint ofthe anode lead-in conductor in the device. This coupling permits slightexpansion of the unit during high temperature operation and contractionthereof after expansion without'placing undue strain on the lead-inseal.

Another feature of this assembly relates to the alignment of thesupporting tensioned hooks of the filamentary cathode in the electrodemount. This involves a metallic guide member having multiple formedslots to guide the tensioned hooks of the filament supporting structureso that unequal expansion in the various filament sections will notdisplace the tensioned hooks from their medial plane and thereby varythe space relation of the filament sections with respect to the othercooperating electrodes.

These and other features of the invention will be more clearlyunderstood from the following detailed description taken in connectionwith the accompanying drawing:

Fig. 1 is a view in elevation of an electron discharge deviceconstructed in accordance with this invention, the device being shownwith portions of the-vessel and the electrodes broken away to illustratethe general assembly of the electrode unit in the vessel;

Fig. 2 is a side view of the electrode unit of Fig. 1 showing thedetails of the supporting assembly on opposite ends of the unit;

Fig. 3 shows the top portion of the unit in perspective to illustratethe relation of the supporting elements of the unit at the upper end ofthe device;

Fig. 4 is a plan view of the upper supporting assembly taken on the line44 of Fig. 1 showing the details of the yoke member and the filamenthook guiding element;

Fig, 5 is a side view of Fig. 4 taken on the line 55 to show thestrengthening rib of the yoke member; and

Fig, 6 is a modified arrangement of the guiding element for the filamenthooks, the other elements of the assembly being shown partly broken awayto clearly illustrate the changes involved.

Referring to the drawing and particularly to Figs. 1 and 2, theelectrode unit embodied in the device and used as an illustrativeexample of the application of the features of this invention to theimprovements of the construction of such devices, is substantiallydisclosed in United States Patent 2,019,492, issued November 5, 1935, to1?. A. S. Hale and V. L. Ronci. This unitary assembly or mount includesa hollow metallic anode H! of large surface area enclosing a fiatcylindrical grid H and a multisection filamentary cathode R2, the anodebeing provided with a pair of channel posts l3 which extend beyond theends of the anode and provide spacing supports for crossshapedinsulating spacer members It and 5 at opposite ends of the unit whichmaintain the grid and filamentary cathode in uniform spacial relationwith respect to the anode surface. The filamentary cathode [2 comprisesa plurality of inverted V-shaped portions or sections connected inseries and forming a single filament having the configuration of adouble M and is supported in a medial plane at the top of the unit by aplurality of tensioned hooks l5 and at the lower end is secured to thespacer l5 by a tie wire ll having multiple arms and a pair of rigid U-shaped anchor wires H8.

The unitary mount is enclosed within a highly evacuated vessel I9, ofvitreous material, such as glass, and being of large area and sufficientmass constitutes a hazard to the enclosing vessel which might befractured by severe shocks imposed on the device by forces directedtowards the vessel in a direction transverse to the axis thereof. Suchforces are extremely detrimental to the proper functioning of the devicewhen the unit is supported only from the stem 20 of the enclosingvessel, due to the large mass of the unit which concentrates the effectin a large deflection of the upper end of the unit and quite often theseforces are sufiicient to cause theupper spacer member I4 to strike theglass wall of the vessel with sufficient force to fracture the glass andthereby impair the usefulness of the device. If the forces are notsufficient to cause the above damage, they are nevertheless great enoughto distort the electrodes and thereby cause unstable operation due tovariations in the characteristics of the device.

These difficulties are overcome and the large mass of the electrodemount is rigidly supported from opposite ends of the vessel, inaccordance with this invention, by providing rigid anchoring supports atopposite ends of the unit to fixedly couple the unit to the .,vessel andto strengthen or reinforce the supporting structure of the unit, wherebylateral impact forces are resisted to alter the axial position of theunitary mount in the vessel. This result is accomplished, however, withthe added requirement that the unit can expand and contract due totemperature variations in the operation of the device. To simplify thesupporting structure at the base of the unitary mount, two rigidconductors or supports 24 are sealed in the stem 26 and extend outwardlyfrom the stem to form external connections for supplying energizingcurrent for the filamentary cathode I2." of the mount. These supportsare rigidly affixed to the bent anchor wires l8 connected to thecathode. The rigid supports in the stem are reinforced by diagonallymounted braces 22 and 23 which are the electrode mount.

formed into downwardly extending wire loops having their ends extendingthrough the lower insulator i5 and interlocked therein and themid-portions of the loops are welded to the rigid supports 2iintermediate the stem 26 and The braces and rigid supports adequatelysustain the lower end of the unit from'the stem 20 of the vessel andprovide a supporting structure for the unit or mount which substantiallyresists deformation by severe shocks imparted to the device in thevicinity of the stem. This resistance is increased by the transversebraces which are mounted at an inward angle from the spacing insulatorG5 to the conductors. Furthermore, this construction greatly simplifiesassembly methods and materially reduces cost of production. It alsoremoves large masses of metal from the glass stem 2i) thereby relievingthe stem from mechanical strain which might endanger the hermetic jointsof the conductors sealed therein.

The upper supporting structure of the unitary mount is shown moreclearly in Figs. 3, 4 and 5 and should be considered in connection withFig. 1 which shows the complete assembly in the device. The upper end ofthe unitary mount is rigidly aihxed to the vessel wall by connecting ametallic yoke member 24 between the insulating spacer M and a rigidleading-in conductor 25, hermetically sealed in the top of the vesseland connected to an external terminal cap 26. The yoke member is formedof relatively wide metallic strap. material, such a molybdenum, and bentinto a rectangular U-shaped element which ismounted in inverted positionacross the short arms of the cross-shaped insulator 14 so that thelongitudinal legs of the yoke member extend toward the mount and theends thereof are bent outwardly to be attached to the insulator I4 bythe rivets which secure the anode channel posts 13 to the insulator. Theintermediate or connecting section 27 of the yoke member carries acentral eyelet 23 which receives the conductor 25 and is rigidly affixedthereto. The connecting section of the yoke member forms a resilient orvyielding portion between the rigid conductor 2'5 and the rigid mass ofthe unit or mount to compensate for expansion and contraction of theunit under varying heating conditions without endangering the seal ofthe rigid conductor 25 with respect to the glass vesse1 and withoutdistorting the electrodes in the mount under the varying conditions.

The yoke member is reinforced by a central strengthening rib, strap orplate 29, which spans the space between the longitudinal legs, the platebeing provided with side flange portions mechanically locked to the legsof the yoke member, the upper and lower edges of the plate being freefrom the yoke member and the insulator M. It will be seen from Fig. 1that the yoke member is mounted in a plane substantially parallel to thebraces 22 and 23 at the lower end of the mount so that forces directedtoward the vessel perpendicular to the plane of the drawing will beresisted by the reinforcing rib 29 and the braces 22 and 2.3 and forcesdirected toward the vessel in the plane of the drawing will be opposedby the wide legs of the yoke member and the sides of thebraces. Anyimpact or shock force imparted laterally between these boundaries willbe equally assimilated without. endangeringthe axial position of themount, in the device. Electron discharge devices, made in accordancewiththis invention, have been subjectedto a standard pendulum impactgravity test in which a hammer on a pendulum travels at a givenacceleration and amplitude to strike the vessel to determine the degreeof shock which can be assimilated by the unit supported in the vessel.Devices of this invention have withstood such a test to a high degree,namely, a value of mg, g being the acceleration of gravity which isthirty-two feet per second and the degree of shock being ten times theacceleration. This force represents a unit of resistance to shock whichis extremely severe, being a value just below the force neces: sary tofracture the glass by the impact hammer.

The filamentary cathode 12 must be maintained in a medial plane in orderto insure stable char acteristics in the operation of the device and toprevent contact of the cathode with the closely spaced laterals of thegrid electrode H. Conditions of operation may cause difierent sectionsof the cathode to expand more than others and this is compensated by thetension springs engag ing the filament hooks. However, difficulties mayoccur due to expansion in some sections which cause the hooks to bedisplaced from their medial plane, thereby producing contact between thefilament and the grid. This difiiculty is avoided, in accordance withthis invention, by providing a metallic guide element 39, formed ofnickel or molybdenum wire, which is bent at a plurality of points toprovide parallel sections forming guide slots for the hook extensionsI6, to maintain them in a medial plane commensurate with the plane ofthe filamentary cathode l2. The guide element 30 extends across the topof the mount and is supported by a pair of posts 3| secured in the topinsulating spacer M. The guide element 39 is a continuous wire ofcircular cross section having distributed portions bent to form theguide slots and extending freely through a circular aperture 32 in thereinforcing plate 29 of the yoke member. This element while formed ofmetal, preferably nickel, is not subjected to heating by inductionduring the evacuation process of the device when the electrodes areinductively heated by a high frequency coil mounted in coaxial relationto the device. .Therefore, the guide element is not distorted since itforms an open circuit member to heating current induced therein, andaccordingly is unaffected by such high temperature heating effects.

The guide element has been shown as extending through an opening in thereinforcing plate of the yoke 24, such an arrangement being practicalfor a construction in which the cathode has more than two sections.Howeven'it is not necessary that the guide element extend through theyoke member if the cathodeis formed of two sections, as shown in Fig. 6.The guide member is subdivided into two sections 33 and 34 which aremounted on the posts 3! and extend toward each other but are separatedby the yoke member, the free ends of the guide sections being bent toformthe guide slots for the hooks Iii.

Although the invention has been described and shown in association witha specific unitary mount of electrodes, it is, of course, understoodthat various modifications may be made in the details of assembly of thesupporting structure of this invention without departing from the scopeand spirit thereof as defined in the appended claims.

What is claimed is:

l. An electron discharge device comprising an enclosing vessel, anelectrode assembly unit within said vessel, means supporting said unitfrom one end of said vessel, conductive means extending from theopposite end of said vessel, a metallic yoke member intermediate saidconductivemeans and said unit, and a rigid rib spanning the space withinsaid yoke member.

2. An electron discharge device comprising an enclosing vessel, anelectrode assembly mount within said vessel, means supporting said mountfrom one end of said vessel, conductive means extending from theopposite end of said vessel, a metallic yoke member intermediate saidconductive means and said mount, said yoke member having longitudinalrigid portions extending from said mount and aconnecting resilientportion attached to said conductive means, and a bridging strap attachedto said longitudinal portions and substantially extending across thespace bounded by said yoke portions.

3. An electron discharge device comprising an enclosing vessel, anelectrode assembly mount within said vessel, means supporting said mountfrom one end of said vessel, a conductor sealed in the other end of saidvessel, a resilient metallic yoke member interconnecting said conductorand said mount, and shock-resisting means bridging the space between andattached to longitudinal portions of said yoke member.

4. An electron discharge device comprising an enclosing vessel, anelectrode assembly unit within said vessel including a plurality ofelectrodes and spacing insulators at opposite ends thereof, a pair ofconductors supporting said unit from one end of said vessel, a bracemember attached to each of said conductors having the ends engaging oneof said insulators, a conductor extending from the opposite end of saidvessel, a yoke member attached to the other spacing insulator and joinedto said latter conductor, and a strengthening insert extending acrosssaid yoke member to resist transverse shock to said unit.

5. An electron discharge device comprising an enclosing vessel, anelectrode assembly mount Within said vessel including a plurality ofelectrodes and spacing insulators at opposite ends thereof, a pair ofconductors supporting said mount from one end of said vessel, a pair ofwire loops having their mid-portion attached to said conductors andtheir end portions interlocked with one of said insulators to reinforcethe sup port oi said mount, a central conductor extending Within saidvessel from the opposite end thereof, a metallic U-shaped strap memberhaving a mid-portion attached to said central conductor and downwardlyextending legs secured to said mount, and a strengthening plateextending between said legs.

6. An electron discharge device comprising an enclosing vessel, anelectrode assembly mount within said vessel, means supporting said mountfrom one end of said vessel, a central conductor extending into theopposite end of said vessel, an inverted U-shaped yoke attached to saidmount and said central conductor, and a rigid partition having sideflanges secured to the side portions of said yoke.

7. An electron discharge device comprising an enclosing vessel, anelectrode assembly mount within said vessel, means supporting said mountfrom one end of said vessel, a central conductor extending into theopposite end of said vessel, an inverted U-shaped metallic yokeintermediate said central conductor and said mount, a strengtheningplate secured to the legs of said yoke and extending across the spacetherebetween, and means connecting said central conductor to a yieldableportion of said yoke to compensate for expansion and contraction of saidmount.

8. An electron discharge device, comprising an enclosing vessel, anelectrode unit therein in cluding an anode,.agrid and a multisectionfilamentary cathode, a pair of insulating spacer members on oppositeends of the electrodes, a plurality of tensioned hook .members engagingsaid multisection cathode, and metallic means supported on one of saidspacer :members, said means having bent portions forming guiding slotsfor said hook members to permit sliding movement in a vertical plane butpreventing displacement thereof from said plane.

9. An electron discharge device comprising an enclosing vessel, anelectrode mount therein including an anode, a grid and a multisectionfilamentary cathode, a pair of insulating spacer members on oppositeends of the electrodes, a

plurality of tensioned hook members engaging said multisection cathode,and .a metallic guide supported in spaced .relation on the insulatingspacer member adjacent said hook members, said guide having spacedparallel sections forming slots for said hook members to maintain saidhook members in a normal plane.

10. An electron discharge device comprising an enclosing vessel, anelectrode mount therein including an anode, a grid and a multisectionfila mentary cathode, a .pair of insulating spacer members on oppositeends of the electrodes, a plurality of tensioned hook members engagingsaid multisection cathode, and a continuous wire guide element supportedon the insulating spacer member adjacent said hook members, said elementhaving spaced folded portions forming slots for said hook members, saidguide element being incapable of distortion by high frequency inductiveheating.

11. An electron discharge device comprising an enclosing vessel, anelectrode assembly unit therein including an anode, a grid and amultisection filamentary cathode, a pair of insulating spacer members onopposite ends of the electrodes, a plurality of tensioned hook membersengaging said multisection cathode, a pair of conductors supporting saidunit at one end of said vessel and connected to said cathode, a centralconductor extending into the oppositeend of said vessel, a metallic yokeat the opposite end of said unit connecting said unit to said centralconductor, a partition extending across said yoke member having'anopening therein, and a Wire guide element for said hook membersextending through said partition.

12. An electron dischargedevice comprising an enclosing vessel, anelectrode assembly unit therein including an anode, a grid and amultisection filamentary cathode, a pair of insulating spacer members onoppositeends of the electrodes, a plurality of tensioned hook membersengaging said .multisection cathode, 1a vpair .of conductors supportingsaid unit atxone end of said :vesseland connected to said cathode, acentral conductor extending into the opposite end of said vessel, ametallic yoke at the oppositeend ofsaid unit connecting said unit 'tosaid central conductor, a partition extending across said yoke member'toreinforce it against lateral shock imparted to said vessel, and a pairof similar metallic guide elements supported on said insulating spaceradjacent said hook members, said elements having bent parallel portionson opposite sides of said hook members to prevent movement thereofparallel to the-plane of said partition.

13. Anelectron discharge device comprising an enclosing vesselcontainingan electrode unit subject to expansion and contraction as .a whole,reinforced conductive means to rigidly support said unit from oppositeends of said vessel to Withstand transverse :shockfcapable of displacingsaid unit 'from'a central position in said vessel,

and one of saidmeans having a transverse yielding portion tocompensatefor expansion and contraction of said unit in an axaldirection.

14. An electron discharge device comprising an enclosing vesselcontaining .a unitary electrode assembly of extensive length which issusceptible to lateral shock capable of distorting the electrodes inthe'unit, and means for'rigidly supporting said assembly from oppositeends of the vessel including a pair of conductors atone end connectingsaid unit to said vessel, a pair of angularly arranged Ueshaped bracesclamped to said unit and afiixed to said conductors, a yoke memberconnecting the opposite end of the unit to said vessel, said yoke beingformed of fiat strip metal, and a reinforcing rib extending across thespace within said yoke member and attached to longitudinal portionsthereof.

15. An electron discharge device comprising an enclosing vesselcontaining a unitary electrode mount of extensive length which issusceptible to lateral shock capable of distorting the electrodes in themount, and means for rigidly supporting said mount from opposite ends ofthe vessel including a pair of conductors at one end connecting saidmount to said vessel, a pair of angularly arranged U-shaped bracesclamped to said unit and afilxedto said conductors, a yoke memberconnecting the opposite end of said mount-to said vessel, said yokebeing formed of fiat strip metal, and a reinforcing rib extending acrossthe space Within-said yoke member and attached to longitudinal portionsthereof, the planes ofsaid braces being substantially parallel to theplanar direction of said reinforcing rib and substantially perpendicularto the direction of extension of said yoke member to providereinforcement against shocks imparted to said vessel from all directionstransverse to the axis thereof.

JOHN W. VEST.

